Motor fuel composition



Patented Feb. 1, 1938 UNITED STATES PATENT OFFICE MOTOR FUEL COMPOSITIONFranz Rudolf Moser, Amsterdam, Netherlands, assignor to ShellDevelopment Company, San Francisco, Calif., a corporation of Delaware NoDrawing. Application-May 11, 1935, Serial N0. 20,987. In' Great BritainMay 16, 1934 6 Claims. (Ol. 44-9) and is more specifically concernedwith further improvements and modifications of the invention disclosedand claimed in my application Serial No. 709,948, filed February 6,1934.

In the operation of compression ignition engines of the Diesel andsemi-Diesel types, and especially in the case of high-speed engines ofsaid types, a relatively long period of time often elapses between theinjection and the ignition of the fuel.

It has already been proposed to remedy this defect by subjecting thefuel to a treatment such as ozonizing, or by adding thereto an ignitionagent having the property of exploding at a temperature below theignition temperature of the fuel. Such agents are, for example, thedecomposition products of percarbonates, perborates and persulfates, orsuch compounds as hydrogen I peroxide, benzoyl peroxide, etc.

These substances, however, have many drawhacks: they are dangerous tohandle, they are unstable and decompose readily at ordinarytemperatures, necessitating the use of various stabilizing agents suchas organic amido-derivatives and, finally, they do not dissolve to asuflicient degree in the fuel to bring about any improvement. Thisnecessitates either the use of additional agents to dissolve saidperoxides, or of elaborate methods to disperse them in the fuel.

In my above-mentioned application Serial No. 709,948 it has beendisclosed that the ignition properties of Diesel fuels, as expressed bytheir cetene numbers, can be considerably improved by the additionthereto of small quantities of tretraline peroxide.

I have now found that even a greater improvement of Diesel fuel oils maybe effected through the addition thereto of a small quantity of a ketoneor an aldehyde peroxide, or of a mixture thereof. The term ketoneperoxide or aldehyde peroxide, as used in this application, designatesan organic peroxide obtained by the reaction of hydrogen peroxide upon aketone or an aldehyde by any suitable method, such, for example, as theprocess described in my copending application Serial No. 11,667, filedMarch 38. 1935.

' to acid on hydrolysisbenzoyl peroxide, as has been stated above, are

Suitable organic compounds which may be used as starting material forthe preparation of ketone or aldehyde peroxides are, for example:acetone, 7

methyl ethyl ketone, diethyl ketone, methyl isopropyl ketone, methylmethyl tertiary butyl ketone, aromatic ketones such as aceto-phenone,benzo-phenone, benzyl ethyl ketone, benzylnaphthyl ketone, andhomologuesand analogues thereof; aliphatic aldehydes,

such as formaldehyde, acetaldehyde, propionalde- 10 hyde,isobutyraldehyde, methyl ethyl acetaldehyde, trimethyl acetaldehyde, andthe like; aromatic aldehydes, as benzaldehyde, toluic aldehydes,cuminol, naphthaldehyde, etc.; and aldehyde-ketone, including bothaliphatic and aroma- 15 tic compounds as pyroracemic aldehyde, isopropylglyoxal, formyl acetone, laevulinic aldehyde, and the like. Polyketonicand polyaldehydic compounds corresponding to the above may also be used,for example, diacetyl, acetyl acetone, acetonyl acetyl acetone, glyoxal,succinic dialdehyde, mesoxalic dialdehyde, phenyl methyl triketone.Furthermore, such compounds may contain substituents as halogen (as inchloral, monochloracetone and the like) nitro, i. e. N02, groups (asm-nitro benzaldehyde, etc.) and the like.

Of the compounds listed above, the peroxides obtained from ketones werefound to be particularly effective, and may therefore especially well beused for raising the cetene numbers of Diesel fuels. It must be pointedout that these ketone peroxides are capable, on hydrolysis, of revertingto ketones, and are therefore radically different from such'compounds,as, for example, benzoyl 35 peroxide, which, being an acid peroxide,reverts Compounds such as generally unsuitable or unsatisfactory for thepurposes of this invention. 40 The magnitude of the effect of theperoxides of the various ketones on the ignition qualities of Dieselfuels was found to depend to a certain degree on the molecular weight ofthe ketones,

the peroxides of ketones of low molecular weight 5 I therefore prefer touse being the most effective. for my process the peroxides of such lowmolecular weight ketones. For example, acetone peroxide is eminentlysuitable for improving Diesel fuel oils, and this invention willtherefore be secondary butyl ketone, 5-

acetyl propionyl, 20

. cases, tetraline peroxide, as will be seen from the further describedwith particular reference to this compound, without, however, being inany way limited thereto, since acetone peroxide is used only as anillustrative example of the ketone and aldehyde peroxides which may beused according to my process.'

The term acetone peroxide is directed to the compound (CaHaOz) n, wheren is equal to 2 or 3, since the product occurs'in dimolecular as well astrimolecular form. It is, understood that either of thwe forms, as wellas a mixture thereof in any proportions is included in the term acetoneperoxide as used herein. The trimolecular form has proved to be the mmsuitable for the object of this invention.

Acetone peroxide can be added to-various oils to be used as Dieselfuels, such as gas oil, solar oil,

Edeleanu kerosene extract, heavy pressure distil- 1 late, coal tarfractions, etc. I

, The quantities to be added depend on the kind and the grade of thefuel oil to be improved, and on the magnitude of'the effect which it isdesired to produce. In general, small quantities of the order of 0.5 to1% are suflicient, since acetone peroxide, being a very effective agent,causes a much more considerable improvement in the cetene numbers ofDiesel fuelsthan it would be possible to achieve by such methods asozonization, or by the addition of equal amounts of such agentsas'hydrogen, benzoyl or even, in some following table:

Table 1 Cet'ene numbers Fuel oil With 1% With 1% Ozonized tetralineacetone peroxide peroxide 45 49 4 tv 49 44 47 49 to 80 85 It will beseen from this table that both low grade (011 No. 1) and relatively highgrade '(oil No. 4) oils can equally well be improved by the method ofthis invention. It may however, be stated that the use of acetoneperoxide is especially advantageous in the case of low-grade Dieselfuels, or in cases when an especially great increase in cetene numbersis desired, and the addition of a correspondingly large quantity of anignition agent, such as 4 or 5%, is therefore necessary. Owing to theirlow solubility in hydrocarbon oils, most of the peroxides, such ashydrogent or benzoyi peroxides, cannot be added to fuel oils in theseproportions, and are therefore unsuitable in such cases, while no suchdisadvantage is attached to theme of acetone peroxide due to its greatersolubility in hydrocarbon oils, as shown in the following table:

Table 2 Solubility at new.

Fuel oil Acetone peroxide Benzo l peroxi e Percent 2. 5 3. 7

Percent Thus, alolar d1 from an East Indies crude, having an originallow cetene number of 31, was improved by the addition of acetoneperoxide as follows:

Table 3 Percent of acetone peroxide added Cetene number No such resultscould have been obtained, for

' solvent. Acetone peroxide in itself is a compara tively explosivecompound, but there is no danger of explosion if it is dissolved in oil.In that connection it may be stated that although acetone peroxide maybe prepared by any known method, a preferred way of achieving thepurpose of this invention consists in extracting it with oil out of amixture of sulfuric acid, persulfuric acid, and acetone, therebyobtaining a concentrated oil solution of acetone peroxide withoutisolating the acetone peroxideitself and thereby incurring the danger ofan explosion. The steps in this procedure may be briefly described asfollows:

' (1) A-solution of persulfuric acid in sulfuric acid is obtained byelectrolysis.

(2) The solution is hydrolyzed by brief heating, for example, 1 minuteat ZOO-220 F., and then cooled to about 5 F. while adding acetone andstirring,

(3) The acetone peroxide formed is extracted from the cooled mixturewith a hydrocarbon oil.

It is of course evident that the peroxides of the other ketones andaldehydes listed above may be prepared by a similar process.

A fuel oil improved by the method of this invention possesses very goodstability and retains its desirable properties during long periods ofstorage as will be shown by the following example:

Into a Venezuelan gas oil with a natural cetene number of 47 wasincorporated 1% of acetone peroxide, the cetene number being therebyraised to 58. After being stored for one month at normal 1 roomtemperatures, it showed no decrease in its active oxygen content and itscetene number; after a subsequent storage of over two months in contactwith iron and zinc, it still retained a oetene number of'57.

It may be added that it is likewise'poss ible to effect a considerableimprovement in the ignition properties of Diesel fuels by adding theretoa small amount of an aldehyde or a ketone peroxide, such, for example,as acetone peroxide, in admixture with certain other substances havingthe property of improving the quality of the fuel oil, such as tetralineperoxide, nitrogen sulfide, esters of nitric or nitrous acids,etc.,since the effectiveness of the latter agents becomes incommensurablygreater in admixture with ketone or aldehyde peroxides and especiallywith acetone peroxide.

In defining herein the ignition values of Diesel fuels, cetene numbershave been used throughout, reference being made to an article of G. D.Boerlage and J. J. Broeze: Ignition Quality of Diesel Fuels'as Expressedin Oeteno Numbers," published 7 in the issue for July, 1932 of the S. A.E. Journal. and a small quantity of a substance selected from I claim asmy invention: the group consisting of tetraline peroxide, nitro- 1. Aliquid fuel for compression ignition engen sulfide, esters of nitricacid and esters oi! nigines containing small quantities of acetonepertrons acid added thereto. 5 oxide added thereto. 5. In the process ofpreparing a liquid fuel for 5 2.- The composition of claim 1 containingless compression ignition engines the step of adding than about 5% ofacetone peroxide added thereto. small quantities of acetone peroxide tothe fuel.

3. The composition of claim 1, containing from 6. A composition ofmatter comprising a liquid to 1% of acetone peroxide added thereto.hydrocarbon motor fuel component and a rela- 10 4. A liquid fuel forcompression ignition engines tively small quantity oi acetone peroxide.10

containing a small quantity of acetone peroxide FRANZ RUDOLF MOBER.

